1. Field of the Invention
This invention relates generally to an electronic device ball grid array (BGA) packaging assembly and, more particularly, to an electronic device BGA packaging assembly, including a thin laminate base plate, that is designed to operate from DC up to 50 GHz with minimal parasitic losses.
2. Discussion of the Related Art
Chip scale packaging is a known technique for environmentally protecting and configuring an electronic chip device and associated circuits within a packaging assembly. Specialized lead frames and circuit connectors are required to electrically couple the electronic device and associated circuits to the various signal lines, power lines and ground lines through the package. Existing electronic packaging assemblies sometimes include high speed input/output (I/O) ports that require costly and bulky high frequency connectors to provide the high speed.
A ball grid array (BGA) is one known I/O device that at least somewhat overcomes these disadvantages, and still provides high speed electrical connections. A BGA is a circuit connection device employing an array of solder balls mounted on a back side of a base plate of the packaging assembly. The solder balls are electrically coupled to the electronic device and associated circuits within the packaging assembly by electrical vias that extend through the base plate of the assembly. A BGA offers compact size, shortened connector lengths necessary for reducing parasitic capacitances and inductances, and good thermal contact to the package assembly for heat sink purposes. Some BGAs are constructed out of ceramic because the device package needs to be hermetically sealed. However, as the ceramic thickness increases, the thermal performance of the packaging assembly decreases.
Known BGAs are realistically limited in their performance to under certain signal speeds. Parasitic capacitances and inductances from the device packaging severely affect device performance for the known packaging assemblies above these signal speeds. In fact, most BGAs only are able to operate below 6 GHz because of their construction. U.S. Pat. No. 6,194,669 does disclose a BGA that is able to operate up to about 28 GHz.
Low cost land grid arrays (LGA) and lead-less chip carriers (LCC) are also well known electronic package construction methods that purport to operate at high frequency. However, LGAs and LCCs have the drawback of thermal cycling problems. Further, LCCs cannot be utilized for more than a certain size, which is dependant on differences between the package and circuit board material's coefficient of thermal expansion (CTE).
Another form of electronic package construction method is the leaded flatpack, which is frequently utilized for low frequency (<10 GHz) applications. For higher frequencies, the electrical leads that are formed to accommodate environmental extremes typically cause increased inductance and signal radiation, which is difficult to accommodate for.